Greenland’s new dinosaur was revealed by CT scan
25 years after the discovery of almost complete dinosaur skulls in East Greenland, an international team of researchers has determined using CT scans that it is a hitherto unknown genus of bipedal, herbivorous dinosaurs, which has been named Issi, which means « called »in Greenlandic. So far, only the two Greenlandic individuals are known and they have been given the species name saaneq, which means «bones» in Greenlandic.
The “cold bones” dinosaur lived for about 214 million. years ago, when East Greenland was connected to Norway and was part of the European continent. The skulls of a young animal and an almost adult specimen of a medium-sized dinosaur were found in Jameson Land in 1994. That skull was quite quickly (incorrectly) identified as a Plateosaurus trotsingensis – a long-necked plant eater from the Triassic period known from hundreds of fossil finds in Germany, France and Switzerland.
The second skull was also thought to belong to one of the extinct Sauropodomorpha species – the prosauropods, which preceded the sauropods, the enormous herbivores that dominated the Earth in Jurassic times and lived for 150 million years.
But now the two older skulls from Greenland have been shown to be different from all other known dinosaurs from the same period.
Extremely high-resolution X-rays
Researchers from Portugal, Germany and Denmark have contributed to the anatomical mapping with micro-CT scan of bones from two skulls, which are put together into 3D models and compared with similar scans of numerous dinosaur skulls from 15 other species of early herbivores, which has been discovered elsewhere in the world after the Greenlandic discovery in 1994.
– The two skulls have a unique anatomy in several areas, for example in the shape and proportions of their bones. The two individuals belong with certainty and completely new art, says Victor Beccari, from NOVA University in Lisbon, according to a press release. Beccari is the lead author of the publication of the scientific article in the journal Diversity.
The two skulls are designated NHMD 164741 and NHMD 164758 and they have lived at the Natural History Museum in Copenhagen since they were found. However, they were lent to Portugal to be digitized with both photogrammetry and µCT scanning, which was used to make a 3D model with a textured surface and to observe the structure of the skull.
Through photography and 3D construction
For photogrammetry, a full walk-around is used with a Nikon D3500 camera, 360 ° with a 10 ° interval between each shot. The image was put together into a 3D model with the Russian software Metashape v. 1.71 from Agisoft.
Both skulls were also sent to the CENIEH research center in Spain to be scanned on a Phoenix V | tome | x S240 microCT scanner capable of making extremely high-resolution 3D X-rays. The result is a stack of 2848 tiff images with a voxel size of 0.08999975 mm, which gives a resolution of 1922 × 562 × 2636 for one skull, NHMD 164741. And a stack of 2821 tiff sizes with voxel images of 0.0679998 mm and a resolution of 1810 × 756 × 2821 for NHMD 164758. The raw files from the scan and the 3D models will be made available on MorphoSource.org.
The US image processing program Avizo v. 9.1 was used to segment the images and remove noise, which resulted in resp. 65 and 73 mesh for each of the two skulls reproduced in the open source program Blender v. 2.92. All masks will be available as wavefront files at MorphoSource.org.
More need to be identified
At the same place in East Greenland, three more skulls of sauropodomorphs are now waiting to be identified.
The skulls of Issi saaneq are currently part of an exhibition at the Museu da Lourinhã in Portugal, but will soon be sent back to Copenhagen, where the Greenlandic finds will be stored in agreement with the National Museum in Greenland.
Several dinosaur bones from East Greenland can be seen at Geocenter Møns Klint, where they are on display while they wait to be examined further.
The article was first published by The engineer.